<article class="material">
  <h1 class="top-gap-0 text-center">{{ course.title }}</h1>
  {% if course.description %}
    <div>
      {{ course.rich_content.content|safe }}
    </div>
  {% else %}
    <div class="flex-center">
      <a class="btn btn-primary" href="{{ next.url }}">立即学习 >></a>
    </div>
  {% endif %}
</article>